The principal aims of this project are to (1) delineate the developmental course of patterns of emotion expressions in affectively positive and negative mother/infant interactions and to assess the relationship of these emotion expression variables to measures of personality/temperament traits, (2) determine the ontogeny of the infant's ability to discriminate or respond differentially to the mother's expressions of joy, anger, and sadness, (3) examine the infant's ability to imitate, learn or perform cognitive/psychomotor tasks following mother/infant interactions characterized by mother's expressions of interest/joy, anger, and sadness, (4) study the developmental changes in selected physiological concomitants of infant emotion expressions in interactions characterized by mother's expressions of joy, sadness, and anger, and (5) evaluate early emotion expression variables, cognitive/psychomotor performance measures (obtained during positive and negative emotion conditions), and patterns of physiological responses as predictors of social, emotional, and cognitive competence in later years. Emotion expressions are measured by Izard's facial movement coding and affect identification systems (Max and Affex), cognitive capacities by measures adapted from Kagan (1978) and Uzgiris and Hunt (1975), infant temperament by Rothbart's Infant Behavior Questionnaire, Mothers Personality by Jackson Personality Research Form, Quality of Attachment by Ainsworth's system and later competence by methods developed by Block and Block, Sroufe, and others. The proposed research will attempt to reaffirm and extend our previous findings on the stability and significance of early emotion expression variables. The distinctly new themes of the present proposal include developmental changes in response to mother's sadness and anger expressions, the ontogeny of discrimination of these two important negative emotions in dynamic mother/infant interactions, the effects of mild stress (sadness/anger emotion expressions) on infant's cognitive/psychomotor functioning, the psychophysiology of infant's emotion expressions, and the analysis of infant's physiological responses during positive and negative mother/infant interactions, and the use of stress-related performance measures and patterns of physiological responses in the prediction of later competence. Evidence for the effectiveness of infant emotion variables in predicting later competence will have significant implications for the early detection and prevention of mental health problems.